It is very important in connection with tractors which are used on very large fields, often rather remote from the place of storage, to have some place on the tractor for conveniently storing accessories such as tools. Also, such tractors often must be left on the field over night and since they often employ rather expensive batteries it is desirable to maintain the battery compartment locked when the tractor is left unattended. To an increasing extent, as field tractors have become larger and carry more equipment such as radios and relatively large batteries, there has been a tendency for such auxiliary equipment to be stolen if the tractor is left unlocked in the field. As a result, it has become customary with large tractors, particularly with those having driver's cabs, to provide means for locking the cab by locking the access doors thereto. This protects the equipment within the cab such as the radio but it does not necessarily insure that the accessories are properly locked up. While it is possible to provide for the accessories being in compartments with separate locks, this requires additional work upon the part of the operator before leaving the tractor and often such additional compartments are thus left unlocked.
While the battery can be placed in the engine compartment, it is customary with large tractors to have the hood cut away adjacent the engine so as to provide better access to certain components of the engine. Thus even if the battery is in the engine compartment, it still can be readily stolen therefrom. Furthermore, the engine compartment is relatively hot and the life of a battery is longer when it is in a cooler location.